Drill spindle driving mechanism



July 12, 1949. w. G. HOELSCHER 2,475,665

DRILL SPINDLE DRIVING MECHANISM Original Filed July 28, 1939 9 Sheets-Sheet 1 INVENTOR.

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DRILL SPINDLE DRIVING MECHANISM Original Filed July 28, 1939 9 Sheets-Sheet 2 y I INVENTOR.

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Willi/11114 II/III!MZU'IIIIIIIIIIIIIIIIM ////A LEEEKE Patented July 12, 1949 DRILL SPINDLE DRIVING MECHANISM William G. Hoelscher, Cincinnati, Ohio, assignor to The American Tool Works Company, Cincinnati, Ohio, a corporation of Ohio Original application July 28, 1939, Serial No. 287,132. Divided and this application April 7, 1945, Serial No. 587,068

7 Claims. (Cl. 74-473) This invention relates to machine tools and is particularly directed to radial drills. More speciflcally, the invention is directed to improvements in the tool spindle operating mechanism.

This application is a division of my Patent No. 2,384.744, issued September 11, 1945 for Drill spindle driving mechanism.

It has been the object of the present inventor to provide an improved arrangement of the power shaft which delivers the power generally to the drill head of the radial drill. The improvement makes it possible to interchange without difliculty the main driving gears, which connect the. motor to the head driving shaft. These gears are disposed in a position where they are convenient- 1y accessible and where their removal does not require any substantial disassembly. Accordingly, in the event that the operator desires a general increase or decrease in speed to the head, he can quickly remove the component driving gears and replace the same with another set of component gears of the desired ratio.

It has been another object of the present inventor to provide spindle driving and feeding transmissions, each shifted by means of a pair of levers for providing the appropriate transmission connections. In each-instance, one of the levers of the pair is for shifting between two ranges and the other is for shifting to the specific speeds or feeds within these ranges.

It has been the further object in this arrangement to provide these levers so that they are more conveniently shifted and so that the operator may determine the position of the respective transmissions by means of improved dials, greatly facilitating correct reading. In both transmissions, that is speed and feed, the dials provide panels having light and dark zones for the respective ranges. When the specific feed or gear shifting means for the transmission of the spindle wherein a number of gears may be shifted from a single cam and wherein the gears shift easily and without frictional resistance. This is accomplished by counterbalancing means associated with each vertically supported gear.

It has been a still further object of the present inventor to provide an improved arrangement of gears whereby fewer gears are required for a given speed, The structure is more compact and less mechanism is required. A struc ture accomplishing this result may consist of a single intermediate shaft, effective for increasing speeds from one to four by the use of a cluster of three gears on the intermediate shaft and clusters of two gears each on the adjacent shafts. One of the adjacent clusters of two gears is shiftable relative to the cluster of three gears to accomplish two speeds, or may be shifted again relative to-the cluster of three gears after the cluster of three gears has been moved to a second gear coupling position, thereby accomplishing two more speeds.

Other objects and certain advantages of the invention will be more fully apparent from the description of the accompanying drawings in which:

Figure 1 is a front view of a radial drill, incorporating the present invention.

Figure 2 is a rear view of the radial drill with the base broken away.

Figure 3 is a top plan view of the radial drill.

Figure 4 is a sectional view taken on line 44, Figure 2.

Figure 5 is a sectional view taken on line B-J, Figure 4.

Figure 6 is a sectional view taken on line 6-6, Figure 1, illustrating the driving and feeding means for the spindle.

Figure 7 is a top plan view of the rear transmission casing of the head with the cover removed.

Figure 8 is a sectional view taken on line B8, Figure 7, illustrating the transmission extending from the drive shaft toward the base of the head.

Figure 9 is a sectional view taken on line 99, Figure 8, further illustrating the transmission.

Figure 10 is a sectional view taken on line I0--l0, Figure 8.

Figure 11 is a sectional view taken on line 3 li-l I, Figure 6, showing a portion of the speed gear shifting means.

Figure 12 is a sectional view taken on line i2-l2, Figure 11, showing the means for rotating one of the shifting cams.

Figure 13 is a view illustrating a development of one of the speed gear shifting cams.

Figure 14 is a. view "illustrating a development of the other of the speed gear shifting cams.

Figure 15 is a sectional view taken on line I-l 5, Figure 6, showing the gearing at the base of the head.

Figure 16 is a sectional view taken on line l6-l6, Figure 15, showing part of the speed gear shifting apparatus.

Figure 17 is an enlarged fragmentary front view of a portion of the head showing the dial and levers for spindle speed changes.

Figure 18 is a sectional view taken on' line IB-IB, Figure 1'7, showing the connection of shifting levers to the shifting means.

Figure 19. is a sectional view taken on line l9-i9, Figure 18, further showing the shifting connections.

Figure 20 is a sectional view taken on line 20-20, Figure 19.

Figure 21 is a sectional view taken on line 2 l-2l, Figure 19.

Figure 22 is a, sectional view taken on line 22-22, Figure 18.

The general construction of the radial drill, in which the present improvements are disclosed, is as follows: A base 59 has a stump 5| rising from one end thereof. A column 52 is rotatably mounted on the stump and has a cap 53 attached to its upper end. An arm 54 is vertically slidably mounted on the column 52. This arm may be raised or lowered so as to place the arm in the proper position for locating the drill at the proper height, relative to the work. The work is mounted on the base 50. The arm is supported and elevated by means of a screw 55 depending from the cap 53 of the column.

A drill head 56 is slidably mounted for longitudinal movement on the arm.54, which projects radially from the column. For this purpose, the arm is provided with a rail 51 along its front face. A driven pinion 58 (Figure 6) engages a rack 59 fixed along the rear face of the rail. This pinion is rotated either by power or by hand through means disclosed and claimed in my Patent No. 2,295,516, issued September 8, 1942.

The power for the drill is derived from an elec-,

tric motor 60, mounted on the short end of the arm. The power is first directed through a shaft 6| into a gear box 62, containing the arm elevating gearing and its control means, disclosed and claimed in a copending application. From the shaft 6|, the power is carried without break to a splined shaft 63, which traverses the drill head and is supported at its outer end in a bracket 64 on the outer end of the arm. Within the drill head the power is taken from the shaft 53 through reversing clutches 65-65 (Figure 8) directly controlled by means of a main power control lever 66 for the drill head.

From the reversing clutches 65-65, the power is delivered to the spindle 6! through speed control gearing. The shifting of this gearing for change of speed is accomplished by means of lever operated cams 68, 69. The system provides for thirty-two speeds. A lever (Figure 17) provides for shift alternately to high and low ranges. Levers ll-l2, movable with respect to a dial plate I3, shift the cams for shiftranges, as indicated on a dial 19. The feed-actuating and control mechanism is described here in a general manner, being fully disclosed in my Patent No. 2,384,744, issued September 11, 1945.

The amount of feed is controlled by means of a. setting and indicator dial 80. The feed connection is controlled manually by means of levers 81-8! (Figure 1) and automatically, by

means of a dog not shown herein, but also disclosed in Patent No. 2,384,744 identified above. This patent also shows dogs on the variable counterbalance additionally control the spindle feed, keeping it within normal limits by automatically stopping the feed, regardless .of the hand setting of the feed dial. A hand wheel 84 provides for manual feed. A lever 85 couples either the hand wheel or the power feed.

Power traverse of the head is controlled by means of a lever 86. A handwheel 81 is provided for traversing the head. by hand. A lever 88 operates the head clamp. Lever 89 controls the ,claimping of the arm to the column and the elevation of the arm. The column is clamped by means of an electric motor 90 on the arm. This ents of the drill structure are not disclosed in detail.

The power to the head The main electric motor 69 is bolted on the short extension of the arm. Its shaft 92 carries a coupling element 93 in toothed connection with a coupling element 93a fixed on the extended end of the power shaft 6|, journaled in the gear box 62 (Figure 5). The shaft 6| is journaled in bearings 94-94 in the respectiveend walls of the gear box. The casing or box 62 is attached to the arm and includes cover plates 95-95 at its respective ends. A pinion gear 96 is attached to the outer end of the power shaft. This gear is constantly in mesh with a gear 97, fixed to a sleeve 98, journaled in spaced bearings 99-99 in a thickened end wall of the casing. The gears 96 and 91 may be removed quite easily and replaced with gears of different size for changing the gear ratio. In other words, if a faster speed is desired the gear 96 may be provided in a larger size and the general speed delivered to the head is correspondingly faster. This interchangement of gears is accomplished by removing the cover 95, loosening the end bracket of the shaft 63 and pulling the shaft from the sleeve 98. Thereupon the nuts holding the gears are removed, the gears replaced, and the parts reassembled.

The power is transmitted from the shaft 6| 5 to the arm elevating mechanism through gear I00, fixed to the shaft 6|, to gear IOI on the reversing shaft assembly I02. The details of this elevating mechanism are disclosed elsewhere and form no part of the present application.

The sleeve 06 provides a splined socket for the driven end of the splined power shaft 63. The outer end of the shaft 63, as stated, is rotatively journaled in the bracket 64, fixed on the outer end of the arm, and is thus disposed along the back of the arm parallel therewith.

The head 56 includes a rear casing section I03 (Fig. 6) which houses the reversing gearing for the spindle, and part of the spindle driving transmission. The head generally described is of the conventional form (Figure 6), that is to say, includes the rear casing I03, a. front casing I04 in which the drill spindle is vertically disposed, and a lower transmission casing or extension I05 of the front casing, connecting the front and rear casings. The arm passes through the space thus provided between the front and rear casings. The rear face of the front casing includes the guide grooves and supporting means which engage upon the rail of the arm.

The splined shaft 63 passes through a long splined sleeve I06 (Fig. 8), the ends of which are journaled in bearings III1I 01, carried by respective bearing brackets I08 I08. These brackets have circular flanges I secured to the ends of the casing I03 by means of screws H0. The assembly of the sleeve in the bearings is maintained by means of washers III, engaging the clutches against shoulders on the sleeve at the inner side of each clutch, and nuts I I2 screwed on the ends of the sleeve and fastening the inner races of the bearings against the washers. The bearing brackets include felt packing rings I I3 surrounding and sealing the ends of the sleeve. One of the brackets includes a removable bushing II4, providing access to one of the nuts I I2, so as to permit removal of the nut I I2 and withdrawal of the sleeve through the other end of the casing.

Reversing driving gears I II I5 are loosely rotatively mounted on the sleeve I06 toward the respective ends thereof. These gears in each instance are journaled on spaced bearings I I6-I I6. fixed on the driving sleeve. Within each gear is a clutch 65. An element II1 of each clutch is keyed to the driving sleeve between the spaced bearings II6-I I6. This element supports a clutch ring II 8, carrying a clutch band I I3.

Since the clutches form no part of the invention described and claimed inthis application, it

is believed unnecessary to show and describe the r clutch details. Generally described, a clutch actuating key I20, mounted in a keyway in the sleeve between the clutches, alternately actuates the clutches for connecting the gears to the splined shaft. This key I has feathered ends engaging under the ends of respective levers I2I. These levers, when rocked, spread the clutch bands and cause them to grip the internal periphery of the gears. A yoke ring I22 encircles the sleeve and key centrally of the clutches and is fixed to the key so as to slide the key longitudinally when actuated. Ayoke I23 (Fig. 9) engages in an annular groove in the yoke ring.

The yoke I23 is fixed on a shifter rod I24 by means of screws I25. The rod is slidably mounted in lugs I26 of the casing. A lever arm I21, bolted to the upper' end of a vertical rod I28, has a ball and socket connection with one end of the shaft I24. The vertical rod I28 is journaled for rotation in an upper lug I20 and a boss I30 in the base 6 wall of the casing. The long main control lever 66 (Fig. 15) is fixed to the extended lower end of the shaft I26 and has its knob end extended out to the front of the head just below the spindle speed shifter lever assembly. Accordingly, horizontal movement of the lever 66 controls the delivery and direction of power entering the drill head.

A reversing idler gear I3I is provided in mesh with one of the gears Hi. This gear (Figs. 8, 9, and 10) is journaled on a short shaft I32 between spaced bearings of the casing. The power is transmitted from gear I I5 through this gear, for the drill return operation, to gear I33, fixed on the splined shaft I34. For the feed and rotation of the drill in boring, a slow speed is obtained through the other gear I I5, meshing directly with a large gear I35, fixed to the shaft I34.

The lubricant pump I36 for the head is fixed to a cover plate I31 in an opening in the back of the head. The pump shaft I38 (Fig. '1) extends into a driving sleeve I33, journaled in bearings I40 in spaced lugs I4I of the cover plate I31. The sleeve I39 includes a gear I42 meshing with driving gear I43, keyed to the driving sleeve I06. The pump has an intake conduit I44 extending up from the sump of the head casing, and an outlet tube I45 extending over to a filter I46, also fixed to the cover plate I31. Lubrication lines I41 extend from the filter to the various bearings of the head. Thus, all of the elements of the lubrication system are secured to the cover plate I31 and may be quickly removed as a unit.

Spindle drive As stated, the gears I33 and I35 transmit rapid drill return movement and slower power or drilling movement respectively, as controlled by the main lever 66. They are fixed to the same shaft, namely, I34. Four speed changes are obtained in the upper or rear casing I03, and these four are stepped up to thirty-two speeds (20 R. P. M. to 1600 R. P. M.) 'in the lower casing of the head at the connection to the spindle.

In addition to gears I33 and I35, three other gears, namely I50, I5I, and I52, large to small, are fixed to the splined shaft I34. These gears I33, I35, I50, I5I, and I52 are held in a cluster on the shaft. End bearings I53 support the shaft I34 in the end wall and a central wall of the casing.

Theshaft I34 includes an extension I54 between the central wall and the other end wall. This extension journals a gear I55, meshing with the gear I43 and forming part of the head traversing gear train, described and claimed in my Patent No. 2,295,516 issued September 8, 1942.

Just below shaft I34 another shaft I56 is rotatably supported in bearings I51-I 51 in the end wall and central wall of the casing parallel with the shaft I34. This shaft is splined and carries shiftable gears I56, I59, I60 and I6I component to the gears I33, I50, I5I, and I52. These gears are in independently shiftable sets of two gears each. In each instance one gear includes a hub I62, upon which the other gear of the set is held by means of a nut I63. The last named gears include annular grooves I64. These grooves I64 are engaged by shifter yokes I65, I66, (Figure 11). The yokes are slidably mounted on a rod I61 and are actuated by means of the cam 68. Each yoke includes a roller I68 engaged in a particular cam track, the arrangement of which is illustrated in Figure 14.

A bevel gear I60 is fixed to the shaft I56 an together rotatlvely' by means of a key I15 on a headed sleeve I18. A nut I11 screwed on the sleeve binds the ears against the inner race of a ball bearing I18 engaged against the head. This gear cluster is shiftable to three positions.

The cluster of two gears just described is shifted by means of a yoke I19 (Figure 11) supported on one end of a pivoted lever I80. The

yoke is slidably mounted on a fixed vertical rod I8I and provides a cross-slotted portion engaged by the roller I82 on the end of the lever. The pivot pin I83 for the lever is mounted in a lug I 84 of the casing. The'other end of the lever carries a roller I85 engaged in a track of the cam I58. A coil spring I85 disposed under pressure between a pin I81 on the lug I84 and the pin I88, carrying the roller I82, counterbalances the weight of the lever, the yoke, and the gear and permits easy shifting. The yoke carries the ball bearing I18 of the cluster and provides a connection in which the gear cluster may rotate and upon which the gear cluster is supported.

Another vertical shaft I89 is journaled in bear-. ings I90-I90 in the upper and lower walls of the lower casing. Access to the lower bearings is had by removal of a cover plate I9I fixed on the base wall of the casing over an opening therein. A shiftable cluster of three gears I92, I93 and I94 is slidably mounted on the splined portion of the shaft I89. A yoke I95 provides for shifting of this cluster and is slidably mounted on a vertical shaft I96. The ball bearing I91 carried by the yoke for permitting rotation of the gears is fixed between gears I92 and I93 and these elements are held on the hub of and against gear I94 by means of a nut I98.

A lever I99 is pivoted on a pin 200 on the lug I84 and has a roller I at one end engaging a cross-slotted portion of the yoke I95. The other end of the lever carries a roller 202 engagin a, cam track of the cam 89. A coil spring 203 under tension between a pin 204 on the lug I84 and the pin 205 carrying the roller 202 is e-fective for counterbalancing the weight of the gear cluster, the yoke, and the lever. Due to these springs I88 and 203, there is very little resistance to overcome in the operation of rotating the cam and shifting the levers.

Another vertical shaft, namely, 206 (Figure 6) is journaled in upper and lower bearings 201-201 fixed in the upper and lower wall of the lower casing. The lower bearing is accessible.

through cover plate ISI. This shaft has three gears, namely, 208, 209 and 2I0 fixed thereto. These gears are not shiftable. The small gear 2I0 is in constant mesh with a bull gear 2 loosely journaled on a double roller bearing 2I2 on the axis of and around the lower end of the spindle.

A driving sleeve 2I3 for the spindle is supported and journaled in an upper roller bearing (not shown) in 9. lug of the casing and a roller bearing 2I5 adjacent the bear ng 2I2. The spindie is in splined connection within this sleeve 2I3 by means of keys M8 and provides the conventional chuck for reception of the drill.

A cluster of two gears 2I1, 2I8 is in splined connection with the driving-sleeve 2I3 and is shifted by means of a yoke 2I9. These gears are integral and provide a sleeve portion having an annular groove 220. The yoke 2I9 engages the groove. The gear 2I8 is adapted to couple with the internal gear of the bull gear and the other, namely, 2", with the gear 208 for coupling either of these gears with the spindle.

Speed shift means The yoke 2I9 includes a vertical-lug portion 222 bolted to a vertical shift rod 223 slidably mounted in plain bearing lugs 224-224 in the casing (Figure 16). A bell crank 225 is pivotally mounted on a pivot pin 228. This bell crank carries a roller 221 adjacent the end of one arm. This roller engages a cross notch in the rod 223. The other arm of the bell crank has a connection with one end of a slide rod 228. The rod 228 is horizontally slidably mounted in the lugs of a control rod assembly housing or casing 229. The

lever 10 is fixed to a vertical stub shaft 230 extending through the top wall of the casing or box 229. The .inner end of the shaft carries a lever arm 23I having a pin 232 engaging a cross groove in the rod 228.

A coil spring 233 under tension between a pin 234 on the end of the yoke supporting arm of the bell crank and a pin 235 on the casing, counterbalances the gear cluster, the yoke and the rod, and takes the weight of these parts off the shifting means for the purposes described heretofore. Thus this gear cluster 2| 1-2I8 has two positions accomplished by Shifting the lever 10 alternately to low or high speed range (Figure 17).

The cam 68 is rotatably mounted, being fixed to a shaft 238 journaled in bearings 231-231. A gear 238 is fixed on one end of the shaft and is in mesh with a gear 239 (Figure 12) mounted on a stub shaft 240 fixed in the casing wall. This gear 239 is in mesh with a ear segment 24! attached to a shaft 242 extending across the casing and journaled in bearings 243-243 in its side walls. An arm 244 is fixed to the shaft at the end opposite the gear segment and is connected by a link 244a to a shifter arm 245 rotativeiy mounted on a shaft 246 journaled in the box 229 (Figure 18). This arm 245 is journaled on spaced ball bearings on the shaft 246 and carries the shifting lever 1I screwed into ts forward side.

The cam 89 (Figure 11) is fixed on a shaft vertically disposed in ball bearings 241-241 in the upper and lower walls of the casing. A gear 248 is fixed to the cam shift at its lower end an meshes with a gear segment 249 (Figure 15) jour naled about the shaft I28 and includes an arm 250 to which a link 25I is attached. The other end of the link is connected to an arm 252 (Figure 18). This arm 252 is journaled on a shaft 253 on ball bearings 254-254 and includes a se ment of bevel teeth 255 meshing with a bevel gear 258 mounted on and fixed to a sleeve 251 journaled on spaced ball bearings 258-258 on the shaft 246. The sleeve has the shifting lever 12 projecting radially therefrom.

The levers H and 12 project through respective vertical slots 259-259 in the face of the casing (Figure 1'7). These slots are spaced apart. The indicator plate 13 is fixed on the face of the casing and has shifting indicia disposed between the slots. Each slot includes a countersunk portion in which a sliding cover plate 260 is. disposed for vertical movement as carried by the shifting lever passing through the plate.

The plate 13 carries all of the spindle speed indicia. The low speeds are indicated by enclosed white areas and the high speeds by enclosed black areas. As stated heretofore, the speeds are divided into these two ranges and the lever controls the shift from one to the other. As indicated in Figure 1'7, the lever 10 has been moved to a position adjacent an enclosed white area 26I at the left hand portion at the top of the indicator plate having been shifted in the direction of the low speed arrow 262 in this panel. For high speeds, the lever is shifted to the right over the enclosed black area 263, including the arrow 264.

For indicating the speeds of the respective ranges, the indicia consists of a series of lines 266 drawn upwardly from the inner edges of the slots. These lines cross each other to form a series of diamond-shaped areas 266. These areas are divided into equilateral triangles by vertical lines 261. Those portions of the diamond-shaped areas on the right-hand side are black and those on the left-hand side are white. Both ranges of speeds read from left to right down each inclined row of diamond-shaped panels. Just below each lever and on the cover plates 260 is an arrow 268 pointing angularly upwardly in parallelism with the lines 265.

As the levers are set in the drawings, Figure 11, the speed of R. P. M. is indicated since 20 R. P. M. is the Only panel section toward which both arrows are pointed. The operator reads the white panels for the reason that the lever '10 is set in the low range of speeds. The operator may very quickly shift the spindle speed from 20 R. P. M. to 193 R. P. M., that is change from one range to the other by moving the lever 10 to the right into the high speed zone. The spindle will then be driven at 193 R. P. M. for the arrows of the shifter levers 1 I and 12 both point to the black areas indicating 193 R. P. M. Assuming the lever 10 to be in the low speed range, a shift can be made from 20 R. P. M. to 31 R. P. M. by moving the lever 1I downwardly into alignment with the last inclined row of areas at which point its arrow will point at 3I. Also, as another example, the operator may shift from 20 R. P. M. to 109 R. P. M. by moving the right-hand lever 12 into alignment with its last inclined row of areas whereupon both arrows will point at I09 in this row.

As may be evident from the speed panel, thirtytwo speeds are possible. Four speeds are delivered to shaft I56 through the four sets of gears. Thus, shaft I'll receives four speeds, shaft I89 eight speeds, shaft 206 sixteen speeds, and the spindle drive sleeve thirty-two speeds. Three positions are provided at shaft I'll (Figure 6) since the gears I13 and I14 may move either with the gears I92 and I93 or these'respective sets of gears may be moved independently. When gear I92 is meshing with gear 209 and gear I14 with I93, gear I13 may be shifted to mesh with gear I92. Thus the speeds available at shaft 206 through gear 209 are eight. When gear I94 is in mesh with gear 200 and gear I93 with gear I14, gear I13 may be shifted one notch higher to mesh again with gear I92. Thus the speeds available at shaft 206 through gear 208 are eight making a total of sixteen speeds either passing through gear 2l-0 to the bull gear 2II to the spindle, or through gear 208 through gear 2" to the spindle for a total of thirty-two speeds.

The drawing shows the system effective for delivering the lowest speed to the spindle, namely 20 R. P. M. (see Figure 17). To produce the 10 mesh of gears necessary for this speed, the levers are set as indicated and the cams rotated so as to shift gears into the following meshing arrangement. The upper cam 66, actuated by shift lever 1 I, shifts gear I6I into mesh with gear I62 leaving the other cluster of gears I69, I60 in neutral (Figure 8). Gear I94 is engaged with gear 209 (Figure 6) by means of the lower cam 69 through lever I60 actuated by shift lever 12. Lever 12,

also through the lower cam. actuates gear I13 to cause it to mesh with gear I92. Lever 10 has moved gear 2I9 into coupling engagement with the internal gear of the bull gear. It is not believed necessary to trace out each of these shifts.

For example,.the operator may Jump the speed from 20 R. P. M. to 1600 R. P. M. if desired. In this event, rotation of the upper cam 66 shifts the gear I69 into mesh with the gear I33 (Figure 8) and maintains the other cluster of gears I59, I60 in neutral. The other cam 69 is effective for moving gear I92 into mesh with gear 209 and gear I14 into mesh with gear I93 (Figure 6). At the same time, the range control lever 10 has been moved to the high speed range which uncouples the bull sear from the spindle and connects the spindle through gears 209 and 211.

Now, each of the shift levers 10, II and 12 are provided with detent means for accurately establishing the various positions. Lever 10 has only two positions, that is, low or high speed. The shaft 230, to which this lever 10 is connected, carries a detent arm 210 providing two detent grooves 21I in its end. A roller 212, carried by a swinging pivoted detent arm 213, is held against the end of the arm containing the detent grooves by means of a coil spring 214 under tension between the roller carrying end of the arm and a stud 215 fixed to the casing Thus, the roller may snap into either one of the grooves for definitely fixing the predetermined shifted position of the lever 10. v The lever 12 provides four positions, each of which is adapted to place the transmission in four different speeds dependent upon the position of the other lever H which also has four positions. For this purpose, the gear (Figure 20) actuated by the lever 12 includes a flange 216 providing four detent grooves or notches 211. A bell crank 218 is pivotally mounted in the casing on a pivot pin 219. One arm 260 of this bell crank carries a roller engaging the notches successively and the other has its end connected to a lug 28I of the casing by means of a coil spring 282 under tension, effective for urging the roller 293 against the grooves.

The other lever H has its operating arm provided with a series of four notches engaged by a detent means of the same nature as that just described. Thus, the two levers H and 12, providing four positions apiece, provide sixteen positions in all and these sixteen positions are doubled by means of the lever 10.

The casing, which carries the levers and dial, also carries the hand wheel 91 for hand traverse of the head along the arm and the control switches 9|, 9| for the column clamp.

The driving sleeve 2I3 for the spindle is journaled in an upper roller bearing (not shown) in the lug of the casing and the roller bearing 2I5 adjacent the double bearing 2 I2. The spindle 61 is in splined connection within this sleeve by means of keys 2I6 and provides the conventional chuck for reception of the drill. The double hearing 2I2 is supported on the boss 286 of the lower wall of the casing and held there by means of a collar 261 engaging the top ofthe bearing. This acme collar 281 is screwed on a sleeve 298 disposed in the boss and has a headed lower end seated in a countersink in a cover plate 289 which encircles the lower end of the driving sleve. A ring 290 is secured by bolts 29I to the under side of the gear and holds the gear on the bearing. The driving sleeve rests on the bearing through a shoulder. A nut 292 on the sleeve engages the bearing against the shoulder and secures the packing 299 in place. Additional packing, shown generally at 294, seals the spindle driving means for preventing leakage of oil from the head.

The spindle feed transmission mechanism, shown in the drawings hereof, conjointly with the speed control mechanism is fully disclosed and claimed in my Patent No. 2,384,745, issued September 11, 1945. Attention also is directed to Patent No. 2,278,262,- issued March 31, 1942 which discloses and claims the adjustable counterbalancing mechanism employed for accommodating tools of various weights in the spindle.

Having described my invention, I claim:

1. Operating means for the spindle of a radial drill including a set of driving gears extending from the power source to the spindle; a lever for shifting the gears into two ranges, additional levers for changing to speeds within the ranges, a gear shifting cam operated by each of said additional levers, and means adjacent each lever for indicating the range and the specific speed.

2. A drill spindle driving means including a driving gear train; a range control lever shiitable from low to high speed range or vice versa, specific speed control levers, an indicator panel having light and dark areas for indicating the low and high speed ranges, said specific speed control levers operating in spaced parallel paths, diamond shaped panels having light and dark halves between said last-named levers, said panels defined by angularly disposed criss-cross lines, and angularly disposed indicating arrows carried by the last-named levers whereby the speed at which the transmission is driven may be determined by reading the panel toward which both arrows point noting the speed indicated in that half of this panel corresponding to the shade at which the range control lever is positioned.

3. In a spindle transmission mechanism including a variable gear transmission; a range control lever, control levers for the speeds within the ranges, an indicator panel having light and dark zones indicating the respective ranges, the lastnamed levers carrying indicator arrows, a diamond shaped area between these levers subdivided into small diamond shaped areas by crossed lines parallel to the sides of the diamond shaped area and providing rows of small diamond shaped areas in the diamond shaped area in the line of direction indicated by the arrows, the levers shiftable to cause the arrows to point along any selected rows whereby the subdivided area pointed low speed range to a high speed range or from a high range to a low ra ge, levers for shifting gears after said first-named lever has been moved to either high speed range or low speed range,

said latter levers movable in spaced parallel paths and an indicator panel disposed between said latter levers, said panel carrying angularly arranged lines, said lines overlapping to form diamond shaped areas carrying the speed indicia.

5. In a spindle operating transmission including a series of gears; means for shifting said gears consisting of a horizontally movable lever for shifting from low to high speed ranges or vice versa, a pair of levers for shifting to speeds within the ranges; said latter levers disposed for movement in spaced parallel paths and including indicator arrows angularly disposed, and a panel between the latter pair of levers including speed indicia arranged in criss-crossed rows respectively disposed at the same angles as the arrows whereby the arrows jointly indicate a single indicia and thus indicate the speed at which the levers are set.

6. In a spindle driving apparatus including a variable speed transmission; a range changing lever, speed change levers, and a panel having panels of light and dark shades in the respective ranges, said panels arranged in angular crisscrossed arrangement between the later levers and the levers movable with respect to the ends of the rows for indicating the respective rows and the particular speed by the coincidence of the rows to which the levers are respectively adjacent.

7. In a spindle driving head a set of horizontally shiftable gears, a cam for shifting said gears, a lever for operating said cam, a set of vertically shiftable gears driven by said first set of gears,

springs respectively sustaining said last-named gears, a cam for shifting said last-named gears, a lever for operating said cam, range change gears for connecting said last-named set of gears to the spindle, a range change lever for shifting said range change gears, said three levers arranged adiacently at the base of the head, and a panel relative to which said levers move, containing the The following referenlces are of record in the file of this patent:

UNITED STATES PATENTS Name Date Hoelscher Sept. 11, 1945 Number 

